Barrel lenght: lots of dangerous big game hunters prefer shorter barrel due to quickness to bring to the shoulder, and less chance of barrel tip getting tangle with brush. A longer barrel will increase sight radius, and gain a few f.p.s. in velocity.
3 models exist(to my knowledge):
Standard: a much straighter stock(less drop at the heel), will kick more to the shoulder but allows quicker game target sight recovery. Wood is plain Jane. I've tried finding a picture of this stock on the net but even CZ-UB web-site has posted the wrong pic of it.
Lux: Is more of a Europeen styled stock, Schnabel fore-end, pig-back cheek piece with a satiny finish.
Safari: Same as Lux but select wood & higher quality finish(more shiny

)